In conventional mobile communication systems, when a packet for a user terminal in an idle state is received, a core network apparatus (e.g., MME (Mobility Management Entity) and SGSN (Serving GPRS Support Node)) provided on a core network sends a paging signal for paging the user terminal to a radio access network apparatus (e.g., RNC (Radio Network Controller)/BSC (Base Station Controller) or eNodeB) provided on a radio access network. The radio access network apparatus sends a paging signal for paging the user terminal in response to the paging signal received from the core network apparatus. The user terminal performs reception processing with the core network apparatus in response to the paging signal sent from the radio access network apparatus (e.g., Non-Patent Literature 1).
In such a mobile communication system, when a packet is received for the user terminal in the idle state, it is known that the core network apparatus or radio access network apparatus applies a paging restriction for restricting the paging to the user terminal. Such a paging restriction is applied, for example, when the core network apparatus or radio access network apparatus is in a congestion state.